Presently, dimmers widely used in the market are designed for a pure resistance load such as an incandescent lamp. These dimmers adjust the effective value of the input voltage through phase control, so as to achieve the brightness adjustment for the lamp. The phase control dimmer mainly includes a leading edge dimmer and a trailing edge dimmer FIG. 1 shows respectively a common connection method of the dimmer in the prior art and an ideal output waveform of the dimmer.
With respect to an LED device, it cannot be connected to a mains supply network directly as an incandescent lamp, and thus the traditional dimmer cannot be directly used for dimming. Instead, a switching power supply needs to be used as a DC driving device for the LED device. Thus, it is desired that such LED driving device can be compatible with the traditional dimmer. However, there is no satisfying device provided in the prior art that can be compatible with the traditional dimmer, and especially no satisfying device is provided that can be compatible with the trailing edge dimmer.